This invention is generally directed to modem timing recovery techniques and is more specifically directed to timing recovery derived from equalized data from an equalizer.
Digital modem receivers normally sample received bauds three or more times per baud in order to determine the constellation point or data being received and establish timing synchronization with the transmitting modem. Increasing the number of samples per baud normally provides better data detection at the expense of increased computational complexity or increased speed of execution. It is desirable to utilize timing recovery information based upon the more reliable equalized data as opposed to unequalized data from the demodulator. As will be explained below, using equalized data for timing recovery at a sampling rate of T/2 results in contention between the equalizer and the timing recovery circuit.
It is an object of the present invention to provide a means for substantially eliminating the contention between a T/2 equalizer and associated timing recovery circuit.